Making truly wireless charging a reality

Ori Mor

Prof. Haim Pekeris St 3, Rehovot, 7670203, Israel

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The convenience and freedom of wireless is invaluable. Just take a look at standard Wi-Fi, first introduced to the general public in 1997. Imagining a world without it is nearly impossible today. If we were required to be tethered to the Internet strictly through wired connections again, it would set us back immeasurably.

When you consider the advancements over the past two decades in mobile computing and the advent IoT technologies it’s fair to ask the question: What’s next for the wireless movement?

Today, mobile devices, smart locks, security cameras and more can communicate seamlessly via Wi-Fi. But all these devices still have an Achilles heel – they all rely on some form of tethered power or a battery that requires regular charging or periodic replacement. Many consumers have become very familiar with the popular contact ‘QI’ charging technology embedded in their newer smartphones. While it is technically wireless power transmission, it is not truly a wireless solution because it requires very close proximity between the charging pad and the device being charged. If to use Wi-Fi on your notebook computer you had to physically touch a wireless router, would you still call it Wi-Fi? Similarly, true wireless charging is one from a distance.

What if mobile and IoT devices could be completely untethered and charged wirelessly - from across the room – no strings or ‘plugs’ attached? If consumers are to enjoy the benefits of a truly wireless experience – internet connectivity, mobile payments and audio transmission have all evolved – it is imperative that the term ’power cord’ is eliminated from their vocabularies altogether. In order to reach that level of innovation, we must look at the road ahead and the wireless charging ecosystem we must build.

Establishing a method of wireless charging

The first step towards a truly wireless world is establishing a method of wireless charging. Similar to the initial concerns around Bluetooth and standard Wi-Fi – many consumers and enterprises question if wireless charging is safe.

The answer is unequivocally yes – but only if the correct approach to wireless charging is being implemented. Let’s dive deeper.

From an engineering perspective, Radio Frequency (RF) technology likely comes to mind for long-range wireless charging. But when RF is concentrated into a tight beam and sent to distances beyond one meter, it begins to disintegrate, and its power transfer is rendered useless. When RF’s power level is increased to compensate for this drop-off, there is a risk of violating the applicable safety standards for radio. RF is man-made radiation and can be very harmful to living organisms, which is why safety limits are reached at such an early point. Displacing the power requirements safely for smart home and mobile devices isn’t within the reach of RF technology.

Enter infrared technology.

Infrared, or IR, can power both mobile devices and smart devices anywhere in the room. It is effective at much longer distances. With IR, you can deliver tens or hundreds of times more power than RF and still stay within safety limits.

Infrared power can be easily packed into a tight beam and will carry its power over long distances. For example, a laser pointer can emit a focused beam of light over a long distance without disintegrating. IR is also much safer. It’s natural. IR is actually responsible for half of the solar energy heating the Earth – and therefore living organisms are more adapted to it.

With all that said, IR is the more viable wireless charging method for use cases that require power over a distance.

Practical device candidates for wireless charging

Now that we established IR as a preferred method of wireless charging, let’s examine the devices that could or should be charged wirelessly.

Devices that require large amounts of constant energy, such as refrigerators, will require an advanced level of wireless charging technology (see below).

Today’s devices that are typically battery-operated that trade power performance and capacity for mobility – such as smart home and mobile devices – are strong candidates for wireless charging applications that deserve the most attention and engineering efforts out of the gates.

There are three important things to consider when determining whether a device is optimal for receiving power wirelessly.

First, device power requirements – long-range wireless power technology is currently geared toward powering devices that have an average wattage of 5 milliwatts to about five watts. For example, a smart lock, a smart speaker and a smartphone would all fall under this category. Second, line-of-sight – IR-based wireless power is a line-of-sight technology. You need to have line-of-sight most of the time between the energy source and the device that’s being powered. This is an important consideration when deciding if a device is a good candidate for wireless power. Ask yourself: Can the IR transmitter and the intended charging device see each other?

Finally ROI – is powering a device wirelessly the best solution? If you have a better solution such as a battery or a power cord, you wouldn’t need wireless power. Efforts should focus on applications where not being able to provide wire-free power is a significant limitation.

Working closely with device manufacturers and governing bodies to innovate, test and establish standards will be critical to creating an integrated and vast ecosystem of wireless charging.

The road ahead

The future wireless charging market isn’t just limited to smart home and mobile devices. The expanding world of beacons and sensors on factory floors could benefit from flexible wireless power too.

A fully wireless charging environment that is easily scalable can improve operational efficiencies and the end-user experience across consumer and enterprise applications. With battery capacity limitations as a non-issue, the wireless charging world will accelerate connected device innovation even faster and further.

The author is Ori Mor, VP Research and Development, Wi-Charge

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